1. Field
This disclosure is concerned generally with a pump-controlling device and specifically with a probe or monitoring device adapted to activate or inactivate a liquid pump on the basis of the electrical conductivity of a given liquid.
2. Prior Art
In recent years, increasing attention has been given to devising safe methods for the storage, transfer and disposal of dangerous, potentially dangerous and/or corrosive liquids. This has been especially true within organizations or industries which, on a regular basis, use relatively large vats, tanks or drums of highly acidic or alkaline solutions for cleaning, neutralizing, etching or otherwise treating materials. For example, the ever-expanding semi-conductor industry commonly uses relatively large volumes of acids (i.e. hydrofluoric, hydrochloric, and the like) for etching purposes. Such acids are often held in open tanks into which various components can be submerged for treatment. In time, these solutions become spent and they must be transferred to other containers for disposal or, perhaps, purification or renewal.
In other cases, such solutions may be part of a continuous flow processing system and, at some point, it may become necessary to monitor the liquid flow through such systems to assure that a liquid having certain properties can either enter or not enter other systems. In any event, it can be appreciated that, for purposes of safety, pollution control or even simple economics, extreme care should be taken in the transfer of many liquids.
Some of the dangers inherent in the transfer of liquids become especially apparent in cases where an operator must physically insert a pump nozzle into a given liquid for transfer to another container which may already hold another liquid. In such cases, care must be taken to assure that a given liquid is in fact the one to be transferred and, if transferred, there will be no potentially dangerous consequences. A typical example would be the inadvertant transfer of water (or an aqueous solution) into a container of concentrated sulfuric acid.
Unfortunately, the identity of a given liquid is not always apparent to the operator of a pump used to transfer the liquid. Because of this, there have been unfortunate instances of personal injuries and property damage occurring as a direct result of placing a pump nozzle into an unknown (or even known) liquid.
In similar fashion, such injuries or damage can occur due to a failure to monitor the nature of liquids continuously flowing through a fluid flow system (e.g. accidental dumping of acids into sewer lines). Because of the likelihood of such injuries or damage, it would be highly desirable to have available a device which could be pre-set to activate or deactivate a liquid pump on the basis of some property of the liquid related to its potential for danger or damage. Ideally, such a device should be sensitive to a relatively unique and distinguishing feature of the liquid. Quite surprisingly, I have found that such device is possible. My discovery is especially surprising in that it is based on relatively simple principles, the combination of which, to my knowledge, has not been previously recognized. Details of my device are described below.